Nanoparticles influence on expression of cell cycle related genes in Drosophila: a microarray-based toxicogenomics study

Relatively little is known regarding the interaction of nanoscale objects with dynamic complex biological systems. Microarray-based toxicogenomics studies may serve as a suitable technique to explore the genome wide effects of nanoparticles on any organism through a single experiment. The influence of nanoporous aluminosilicate nanoparticles (NP), citrate-capped gold NP, lipophilic silica NP, BSA-capped silver NP, and lipophilic zinc oxide NP were studied on 75 cell cycle-related genes of adult Drosophila melanogaster. Microarray experiments were conducted after the flies were fed with NP-mixed media for 15 days. Data showed that silver, zinc oxide, and alumino silicate NP predominantly perturbed cell cycle genes, whereas gold and silica NP exerted the least influence on these genes.     

Source identification of particulate matter and associated intake of elements through inhalation in an industrial area of Odisha,India

Particulate matter concentrations were measured in an industrial region in the Ganjam district of Odisha. The average levels of suspended particulate matter (SPM) were measured to be 142 ± 8 and PM₁₀ of particulate matter with a size of less than 10 micrometers (PM₁₀) to be 50 ± 15 μg m^?3. Out of the 14 elements determined, Ca, Na, Mg, Fe, and K contributed more than 95% of the total weight. In enrichment factors, the trace elements, i.e., Zn, Pb, Cd, and Hg were observed to be highly enriched in the SPM and PM₁₀. Factor analysis indicates that more than 75% of the variance was due to five component factors, which have eigenvalues greater than 1. Intake of elements through inhalation route to adults has been estimated.     

长江口溶解无机碳循环的地球化学研究

于2005年6月对长江口23个站点的溶解性无机碳及其同位素组成进行了采样调查。结果发现长江河流区水体的pCO2均处于过饱和状态,但在进入河口区后发生大幅度的下降;δ13CDIC为-10.0‰～-0.9‰,且随盐度发生梯度性变化;DIC和δ13CDIC值偏离河水、海水混合线,显示了长江河口碳的复杂生物地球化学过程,包括内部碳酸盐岩体系及外部生物的作用:河流区主要受水-气界面CO2逸散的影响;河口区主要受光合作用的影响;海岸区则主要受碳酸盐类矿物沉淀作用的影响。     

Measurement of natural radioactivity in chemical fertilizer and agricultural soil: evidence of high alpha activity

People are exposed to ionizing radiation from the radionuclides that are present in different types of natural sources, of which phosphate fertilizer is one of the most important sources. Radionuclides in phosphate fertilizer belonging to ²³²Th and ²³⁸U series as well as radioisotope of potassium (⁴⁰K) are the major contributors of outdoor terrestrial natural radiation. The study of alpha activity in fertilizers, which is the first ever in West Bengal, has been performed in order to determine the effect of the use of phosphate fertilizers on human health. The data have been compared with the alpha activity of different types of chemical fertilizers. The measurement of alpha activity in surface soil samples collected from the cultivated land was also performed. The sampling sites were randomly selected in the cultivated land in the Midnapore district, which is the largest district in West Bengal. The phosphate fertilizer is widely used for large agricultural production, mainly potatoes. The alpha activities have been measured using solid-state nuclear track detectors (SSNTD), a very sensitive detector for alpha particles. The results show that alpha activity of those fertilizer and soil samples varies from 141 Bq/kg to 2,589 Bq/kg and from 109 Bq/kg to 660 Bq/kg, respectively. These results were used to estimate environmental radiation exposure on human health contributed by the direct application of fertilizers.     

Biosynthesis of silver nanoparticles using <Emphasis Type="Italic">Myristica fragrans</Emphasis> seed (nutmeg) extract and its antibacterial activity against multidrug-resistant (MDR) <Emphasis Type="Italic">Salmonella enterica</Emphasis> serovar Typhi isolates

Biosynthesis of nanoparticles has received increasing attention due its effective mode of action, eco-friendly preparation methodology, and less cytotoxicity. In the present study, silver nanoparticles (AgNPs) from aqueous seed extract of Myristica fragrans (nutmeg) were characterized. Gas chromatography–mass spectrometry (GC–MS) analysis revealed the presence of bioactive components acts as effective in reducing and capping agents for converting AgNO₃ to AgNPs. The UV-Vis absorption spectrum of the biologically reduced reaction mixture showed the surface plasmon peak at 420 nm, which is the characteristic peak of AgNPs. The functional molecules present in the M. fragrans seed extract and their interaction with the AgNPs were identified by the Fourier transform infrared spectroscopy (FT-IR) analysis. X-ray diffraction (XRD) analysis confirmed the face-centered cubic crystalline structure of metallic silver nanoparticle and diameter was calculated using Scherrer’s equation. Transmission electron microscope (TEM) image showed spherical shaped particles with an average size of 25 nm. The scanning electron microscopy–energy dispersive spectroscopy (SEM–EDS) confirmed the presence of elemental silver. The antibacterial activity of biosynthesized AgNPs was evaluated against multidrug-resistant (MDR) Salmonella enterica serovar Typhi (S. Typhi) according to agar well diffusion, MIC (minimum inhibitory concentration), and IC₅₀ (inhibitory concentration 50%). The results confirm that bacterial growth was significantly reduced in a dose-dependent manner. Further, the cytotoxic effect of biosynthesized AgNPs on rat spleenocytes was analyzed. Thus, it is suggested that the nutmeg-biosynthesized AgNPs could be a lead drug and used effectively to control the MDR S. Typhi, thereby reducing public health issues and environmental pollution.     

Prediction of enteric methane emission from cattle using linear and non-linear statistical models in tropical production systems

The objective of this study was to develop linear and nonlinear statistical models to predict enteric methane emission (EME) from cattle (Bos) in the tropics based on dietary and animal characteristic variables. A database from 35 publications, which included 142 mean observations of EME measured on 830 cattle, was constructed to develop EME prediction models. Several extant equations of EME developed for North American and European cattle were also evaluated for suitability of those equations in this dataset. The average feed intake and methane production were 7.7?±?0.34 kg/day and 7.99?±?0.39 MJ/day, respectively. The simple linear equation that predicted EME with high precision and accuracy was: methane (MJ/day)?=?1.29_(±0.906)?+?0.878_(±0.125)?×?dry matter intake (DMI, kg/day), [root mean square prediction error (RMSPE)?=?31.0 % with 92 % of RMSPE being random error; R ²?=?0.70]. Multiple regression equation that predicted methane production slightly better than simple prediction equations was: methane (MJ/day)?=?0.910_(±0.746)?+?1.472_(±0.154)?×?DMI (kg/day) – 1.388_(±0.451)?×?feeding level as a multiple of maintenace energy intake – 0.669_(±0.338)?×?acid detergent fiber intake (kg/day), [RMSPE?=?22.2 %, with 99.6 % of MSPE from random error; R ²?=?0.84]. Among the nonlinear equations developed, Mitscherlich model, i.e., methane (MJ/day)?=?71.47_(±22.14.6)?×?(1 - exp{?0.0156_(±0.0051)?×?DMI (kg/day), [RMSPE?=?30.3 %, with 97.6 % of RMSPE from random error; R ²?=?0.83] performed better than simple linear and other nonlinear models, but the predictability and goodness of fits of the equation did not improve compared with the multiple regression models. Extant equations overestimated EME, and many extant models had low accuracy and precision. The equations developed in this study will be useful for improved estimates of national methane inventory preparation and for a better understanding of dietary factors influencing EME for tropical cattle feeding systems.     

Assessment of biological and biochemical indicators in soil under transgenic Bt and non-Bt cotton crop in a sub-tropical environment

There is concern that transgenic Bt-crops carry genes that could have undesirable effects on natural and agro-ecosystem functions. We investigated the effect of Bt-cotton (expressing the Cry 1Ac protein) on several microbial and biochemical indicators in a sandy loam soil. Bt-cotton (MRC-6301Bt) and its non-transgenic near-isoline (MRC-6301) were grown in a net-house on a sandy clay loam soil. Soil and root samples were collected 60, 90, and 120 days after sowing. Soil from a control (no-crop) treatment was also included. Samples were analysed for microbial biomass C, N and P (MBC, MBN, MBP), total organic carbon (TOC), and several soil enzyme activities. The microbial quotient (MQ) was calculated as the ratio of MBC-to-TOC. The average of the three sampling events revealed a significant increase in MBC, MBN, MBP and MQ in the soil under Bt-cotton over the non-Bt isoline. The TOC was similar in Bt and non-Bt systems. Potential N mineralization, nitrification, nitrate reductase, and acid and alkaline phosphatase activities were all higher in the soil under Bt-cotton. Root dry weights were not different (P > 0.05), but root volume of Bt-cotton was higher on 90 and 120 days than that of non-Bt cotton. The time of sampling strongly affected the above parameters, with most being highest on 90 days after sowing. We concluded from the data that there were some positive or no negative effects of Bt-cotton on the studied indicators, and therefore cultivation of Bt-cotton appears to be no risk to soil ecosystem functions.     

Effect of fatty acids and oils on photodegradation of azadirachtin-A

Azadirachtin-A on exposure to UV-light (254 nm) as a thin film on glass surface gave a isomerised (Z)-2-methylbut-2-enoate product. Half-life of azadirachtin-A as thin film under UV light was found to be 48 min. Azadirachtin-A was irradiated along with saturated and unsaturated fatty acids, and fatty oils under ultra-violet light as thin film. Saturated fatty acid increased the rate of photodegradation of azadirachtin-A, whereas unsaturated fatty acids such as oleic, linoleic and elaidic acid reduced the rate of degradation. Castor, linseed and olive oil accelerated the rate of degradation, whereas neem oil showed no or little change in the rate of degradation of azadirachtin-A. None of these fatty acids and fatty oils were effective in controlling the rate of degradation of azadirachtin-A under UV-light as thin film.     

A comparison of biochemical responses to oxidative and metal stress in seedlings of barley, Hordeum vulgare L

Biochemical responses on the bases of activities of antioxidant enzymes; peroxidase, catalase, superoxide dismutase and glutathione reductase as well as estimations of total protein, lipid peroxidation and thiols in the form of protein, non-protein, glutathione and phytochelatin measured in growing seedlings of barley, Hordeum vulgare L., from Day 2 through 8 were compared following treatment of seeds for 2 h with oxidative agents, paraquat 5 x 10(-5), 10(-4), 10(-3) M, H2O2 10(-3), 5 x 10(-3), 10(-2) M and a metal salt, CdSO4 10(-5), 10(-4), 10(-3) M. A significant induction of all antioxidant enzymes along with an increase in the levels of protein, lipid peroxidation and glutathione was noted in response to oxidative stress, CdSO4 induced significant peroxidase and catalase activities but not superoxide dismutase. In a marked contrast from oxidative stress, CdSO4 decreased glutathione reductase activity as well as glutathione levels but increased phytochelatin level. The differential biochemical responses thus underlined the crucial involvement of glutathione and phytochelatin in the oxidative and metal-induced adaptive responses, respectively.